Have you used any imperative, statically typed language that's compiled, such as C#, C++ or Swift? Previous knowledge of a purely functional language would be useful as well, but not required. Knowing Java helps with debugging and working with libraries built from Java, which depending on what one is doing (Android for example or using JSoup for scraping), is inescapable. You'll end up having to semi learn Java along the way, at least from what a friend told me (I already knew Java previously, so cannot comment on that). Scala, like C#, has extension methods to make dealing with Java libraries easier though, but it still doesn't solve things like JDK annoyances (type erasure).
If you're only familiar with scripting languages, it's going to be sort of a leap into learning Scala and could be done I think, though probably not the language I would recommend starting with since it's easy to abuse. The syntax is nowhere the same, but Scala sort of reminds me of the "Perl of statically compiled languages" in that you can write some really obtuse code without even trying if you're not careful. I don't think that's a bad thing necessarily, because it's a language that gives you a lot of flexibility (and more than enough rope to hang yourself). If you work with someone else, be sure to discuss some sort of agreed upon standard to using Scala, else you'll end up with some messy code.
Scala looks a bit like Python in parts as well as Swift, but I consider it more closer to a progressive version of C# with F# mixed into it.
If you're only familiar with scripting languages, it's going to be sort of a leap into learning Scala and could be done I think, though probably not the language I would recommend starting with since it's easy to abuse. The syntax is nowhere the same, but Scala sort of reminds me of the "Perl of statically compiled languages" in that you can write some really obtuse code without even trying if you're not careful. I don't think that's a bad thing necessarily, because it's a language that gives you a lot of flexibility (and more than enough rope to hang yourself). If you work with someone else, be sure to discuss some sort of agreed upon standard to using Scala, else you'll end up with some messy code.
Scala looks a bit like Python in parts as well as Swift, but I consider it more closer to a progressive version of C# with F# mixed into it.